Researchers at the University of Illinois have 3D printed an origami-inspired crawling robot. Recently published in the academic journal Smart Materials and Structures, the new innovation holds serious potential for re-thinking folding principles and bio-inspired design in machine industries, say its creators.

While bio-inspired robots are certainly nothing new, the U of Illinois gadget approaches this field from an entirely new vantage point. Rather than create a robot mimicking human qualities, Assistant professors of mechanical and science engineering Aimy Wissa and Sameh Tawfick drew inspiration from often overlooked life-forms such as earthworms, bacteria, and Venus Flytraps.

Similarly, the team’s use of materials proved radical, yet effective: the crawling robot successfully combines cutting-edge 3D modelling and 3D printing techniques with age-old folding methods such as origami. The result is a small, slinky robot quite unlike anything you’ve ever seen before.

"[Our] paper presents the design of a bio-inspired crawling robot," said Wissa. "The robot uses origami building blocks to mimic the gait and metameric properties of earthworms and directional material design to mimic the function of the setae on earthworms that prevents backward slipping."

With the help of graduate student Alexander Pagano and undergraduates Tongxi Yan and Brian Chien, Wissa and Tawfick used origami paper folding principles to build and actuate specialized mechanisms and machines. Possible integration could be anything from small, inexpensive robots to deployable adaptive structures.

Tawfick explained that chief inspiration came from the rapid movement of soft plants such as the Venus Flytrap as well as the swimming motions of uni-flagellated bacteria. Both types of organisms use the extreme flexibility of their bodies to quickly snap, enabling quick motions while saving energy.

Equally original was the team’s use of origami-inspired techniques. Specifically the U of Illinois researchers explored the concept of the Kresling crease pattern, a chiral (or asymmetric) tower with a polygonal base. By coupling expansion and contraction movements with longitudinal and rotational motion, this type of origami tower is similar to a screw. The team decided to add buckling instabilities in order to accomplish that earthworm-inspired “snapping” motion from small inputs.

This motor rotation, alongside fast expansion and contraction, is what gave the worm-like robot its crawling gait. The origami-meets-3D-printing gadget can go forward in a straight line, turn left and right, and generally follow a predetermined path without slippage.

The team’s research is the first of its kind of to use virtual folds for analyzing panel bending in snapping origami towers. Consequently, the design offers serious advantages in energy consumption and simplifying open loop locomotion control.

"The ability to produce a functional and geometrically complex 3D mechanical system from a flat sheet introduces exciting opportunities in the field of robotics for remote, autonomously deployable systems or low cost integrated locomotion," write the U of Illinois researchers.

According to its creators, the worm-inspired robot also opens up vast possibilities for using novel material combinations and patterns in machines. The same design can also be used in manipulations, booms, and active structures.

Looking ahead, the team wants to keep experimenting with their design and see how far the innovation can stretch, so to speak. On future development, Wissa noted, "we plan to continue to build on our findings to design, model, and test bio-inspired modular robots capable of multiple modes of locomotion."